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http://www.policemag.com/channel/weapons/articles/2014/09/revisiting-the-21-foot-rule.aspx
Departments : The Winning Edge Revisiting the "21-Foot Rule"
The Tueller Drill is often evoked as justification by officers after a
shooting.But is it scientifically defensible?
September 18, 2014 | by Ron Martinelli
Photo: Martinelli & Associates
For decades now many American officers have heard use-of-force instructors
discuss the "21-Foot Rule" during officer safety, firearms, and deadly force
training. As a use-of-force instructor and a practicing forensic police
practices expert, I have also trained and testified to this concept myself.
The 21-foot rule was developed by Lt. John Tueller, a firearms instructor
with the Salt Lake City Police Department. Back in 1983, Tueller set up a
drill where he placed a "suspect" armed with an edged weapon 20 or so feet
away from an officer with a holstered sidearm. He then directed the armed
suspect to run toward the officer in attack mode. The training objective was
to determine whether the officer could draw and accurately fire upon the
assailant before the suspect stabbed him.
After repeating the drill numerous times, Tueller-who is now retired-wrote
an article saying it was entirely possible for a suspect armed with an edged
weapon to fatally engage an officer armed with a handgun within a distance
of 21 feet. The so-called "21-Foot Rule" was born and soon spread throughout
the law enforcement community.
But is the "21-Foot Rule" a forensic fact or a police myth?
Reactionary Gap
Tueller designed his firearms action-reaction experiment as a training
device to help his students better understand the concept of the
"reactionary gap." The reactionary gap is a human factors formula that
compares action vs. reaction. In humans, sudden action is usually faster
than a defensive response or reaction. The closer an assailant is to an
officer, the less time an officer has to defensively react to any aggressive
action the assailant makes.
Tueller has said in video interviews that he never designed nor presented
his firearms training drill as an organized, outlined, and implemented
research project involving the applied sciences of psychophysiology,
physics, and related human factors. No forensic testing, examination,
reconciliation of data, or scientific oversight of a research model was ever
conducted.
During the past 30 years since the 21-Foot Rule has become informal doctrine
within the law enforcement community, I have heard it misstated,
misrepresented, and bastardized by use-of-force, firearms, and police
practices experts from all sides. I actually reviewed an officer-involved
shooting case where an officer with a carbine shot and killed a suspect
armed with a knife from a distance of more than 150 feet and attempted to
use the "Tueller Drill" as his defense.
Instructors and experts also seem to have forgotten that the original
scenario of Lt. Tueller's drill involved an officer with a holstered sidearm
drawing and accurately firing his weapon. In the vast majority of
officer-involved shootings I have investigated or reviewed, the officers
already had their guns out of their holsters and were either at the "low
ready" position or directly aimed at the suspects who were either armed with
knives or furtively reaching into their waistbands.
So what are the real forensic facts that might assist officers with their
officer safety and deadly force determinations?
Actually, there are no forensically proven facts that I am aware of that
specifically verify or conclusively establish that a suspect armed with an
edged weapon will more likely than not be able to seriously injure or kill
an officer armed with a sidearm on all occasions and circumstances. The
truth is that the 21-Foot Rule should not be considered to be an absolute
rule at all because there are too many variables involved at this point to
call it a "rule." Let's discuss them.
The Variables
Psychophysiology-This is the study of how the brain influences and affects
physiological function. Science tells us that humans possess both a
forebrain and a midbrain. The forebrain is where cognitive processing and
decision-making take place. The midbrain plays a role in situational
awareness, sleep, arousal, alertness, and trained and subconscious memories.
When an officer experiences a threat, it takes on average .58 seconds to
experience the threat and determine if it is real. It then takes on average
.56 to 1.0 seconds to make a response decision. Humans have five possible
responses to threat: defend (fight), disengage (retreat), posture (yell,
point a finger, act aggressive), become hypervigilant (panic, confusion,
freezing, using force excessively), and submit (surrender).
When a human is threatened, the brain automatically infuses the body with
adrenalin (stimulant), endorphins (pain blockers), and dopamine (euphoric
pain blocker). The body uses these chemicals to help us survive an encounter
by making us faster, stronger, and more pain tolerant. However, these same
chemicals can also significantly diminish our performance under intense
stress by causing such problems as perceptional narrowing (tunnel vision),
loss of near vision, and auditory occlusion (reduced hearing) or exclusion
(loss of hearing). This ultimately negatively affects our chances of
surviving a violent encounter.
Under the intense stress normally associated with deadly force threat
scenarios and while under the influence of survival chemicals, the body's
basal metabolic rate, measured by heart rate, blood pressure, and
respiration, climbs significantly in milliseconds. This dynamic can cause
further psychophysiological impairments such as vasoconstriction, which can
impair weapon manipulation, cognitive processing, and stress memory recall
following an encounter.
Equipment and competency-Several factors affect an officer's survival
against an attacker. For instance, an officer or detective whose sidearm is
secured in a Level III holster will certainly have a slower draw-to-target
acquisition time than an officer drawing from a Level I holster. An
officer's experience and competency with his or her holster system and
combat shooting style are also critical human factors in that officer's
ability to draw, move off the line of attack, and direct accurate fire upon
an armed assailant.
Accuracy of fire at close distances-The average officer in static firearms
qualifications (non-timed, standing, and shooting without moving) can hit
the 9 and 10 rings far more often than not from the five-yard line. However,
research of actual OIS incidents has shown that officers can only accurately
hit their moving assailants 14% of the time in life-or-death situations from
distances of only two to 10 feet. On the other hand, assailants were able to
successfully engage and hit officers 68% of the time within those same
distances.
Perception lag-Once the average officer gets on target, it takes him or her
.56 seconds to make a decision to commence shooting. However, it then takes
that same officer .25 to .31/100ths of a second per trigger pull to fire. As
the deadly force scenario rapidly evolves, it takes that same officer on
average .5 to .6 seconds to realize that the threat has passed and to stop
shooting. This is because of a psychophysiological dynamic referred to as
"perception action-reaction lag time."
The reason why some suspects are found to have entry wounds in their sides
and backs when the officers who shot them say the suspects were facing them
when they fired is often the perception action-reaction lag time and the
manner in which information was processed by the officers' brains. This is
pretty sophisticated information for a criminal or civil jury to understand
and consider.
Fantasy or Forensic Fact
The fields of contemporary police practices and applied sciences are rapidly
changing. Applied science, by its nature, supports or rejects hypotheses and
theories based upon the reconciliation of scientific statements, facts, and
evidence. However, law enforcement is more inclined to be archaic and
married to non-forensic, speculative dogma that often goes unchallenged and
becomes widely accepted as fact.
It is my opinion that Lt. John Tueller did us all a tremendous service in at
least starting a discussion and educating us about action vs. reaction and
perception-reaction lag. This has certainly saved many lives within our
ranks. However, it is certainly time to move forward with a far more
scientific analysis that actually seeks to support or reject this
hypothesis.
Whether the "21-Foot Rule" is an applicable defense in an officer-involved
shooting actually depends upon the facts and evidence of each case. The
shooting of a knife-wielding suspect at less than 21 feet by an experienced,
competent, and well-equipped officer who has the tactical advantage of an
obstruction such as a police vehicle between herself and her attacker might
be inappropriate. But the shooting of a knife-wielding assailant at more
than 21 feet by an inexperienced officer, wearing a difficult holster
system, with no obstructions between herself and the attacker might be
justified.
As the 1989 U.S. Supreme Court ruling in Graham v. Connor (490 U.S. 386, 109
S.Ct) has eloquently stated, each high-risk encounter during a rapidly
evolving situation is unique. My sense is that future research may
underscore that legal principle with respect to the Tueller Drill.
Note: The author would like to thank forensic expert team members Homicide
Lt. Bob Prevot (Ret.), M.A., ballistic scientist/firearms expert Lance
Martini, M.S., firearms expert Larry Nichols, and NSW operational
psychologist and psychiatry professor Douglas Johnson, Ph.D., for reviewing
and contributing to this article.
Ron Martinelli, Ph.D., is a nationally renowned forensic criminologist
specializing in police death cases, use of force, human factors, and
psychophysiology. Dr. Martinelli is a retired law enforcement officer who
directs the nation's only multidisciplinary civilian Forensic Death
Investigation Team at Martinelli & Associates, Inc. He can be reached at
(951) 719-1450 and www.martinelliandassoc.com. His firm is presently engaged
in a major forensic scientific project reanalyzing the "21-Foot Rule." If
you are interested in volunteering for this important project, please
contact his office.
Related Video:
http://outfront.blogs.cnn.com/2014/08/22/how-are-cops-trained-for-deadly-for
References:
1.. The Tueller Drill, Video Interview with Lt. Dennis Tueller (Ret),
GunWebsites, 03-25-11
2.. How Close Is Too Close? (Article) Tueller, Dennis, SWAT Magazine,
03-1983
3.. Understanding & Leveraging the Psychophysiology of Emotional
Intensity, Sztajnkrycer, Matthew, M.D., Ph.D., Force Science Institute®,
Minnesota State University, Presentation at San Jose (CA) Police Department,
02-08-10
4.. Ibid.
5.. Processing Under Pressure: Stress, Memory and Decision Making in Law
Enforcement, Sharps, Matthew, Ph.D., © 2010, Loose Leaf Publishing,
Flushing, N.Y.
6.. Some fundamental of Human Performance: Applications to Police
Activities, Schmidt, Richard, Ph.D., Force Science Institute®, Minnesota
State University, Presentation at San Jose (CA) Police Department, 02-09-10
7.. Violent Encounters - A Study of Felonious Assaults on Our Nation's Law
Enforcement Officers, U.S. Department of Justice, Federal Bureau of
Investigations, Publication #0383, 2006
8.. Reaction Times in Lethal Force Encounters, The Tempe Study, (Article)
Lewinski, Bill, Ph.D., Hudson, Bill, Ph.D., The Police Magazine, Sept/Oct.,
2003, pp. 26 - 29
9.. The Psychology and Physiology of Deadly Conflict in War and in Peace,
Grossman, D.A., PPCT Research Publications, 2004
10.. Deadly Force Encounters: What Cops Need to Know to Mentally and
Physically Prepare for and Survive A Gunfight, Artwhol, A, Christensen, L,
Paladin Press, 1997
11.. Sharpening the Warrior's Edge: The Psychology & Science of Training,
PPCT Research Publications, 1995
12.. Motor Learning and Performance, Schmidt, R.A. and Wrisberg, C.A., 3rd
Edition, Human Kinetics Publishers, 2004
13.. Human Perception and Performance, (Article) Keetch, K.M., Schmidt,
R.A., & Young, D.E., Journal of Experimental Psychology, 2005, No. 31,
970-978
Tags:
Tueller Drill Knife Attacks Winning Edge
Departments : The Winning Edge Revisiting the "21-Foot Rule"
The Tueller Drill is often evoked as justification by officers after a
shooting.But is it scientifically defensible?
September 18, 2014 | by Ron Martinelli
Photo: Martinelli & Associates
For decades now many American officers have heard use-of-force instructors
discuss the "21-Foot Rule" during officer safety, firearms, and deadly force
training. As a use-of-force instructor and a practicing forensic police
practices expert, I have also trained and testified to this concept myself.
The 21-foot rule was developed by Lt. John Tueller, a firearms instructor
with the Salt Lake City Police Department. Back in 1983, Tueller set up a
drill where he placed a "suspect" armed with an edged weapon 20 or so feet
away from an officer with a holstered sidearm. He then directed the armed
suspect to run toward the officer in attack mode. The training objective was
to determine whether the officer could draw and accurately fire upon the
assailant before the suspect stabbed him.
After repeating the drill numerous times, Tueller-who is now retired-wrote
an article saying it was entirely possible for a suspect armed with an edged
weapon to fatally engage an officer armed with a handgun within a distance
of 21 feet. The so-called "21-Foot Rule" was born and soon spread throughout
the law enforcement community.
But is the "21-Foot Rule" a forensic fact or a police myth?
Reactionary Gap
Tueller designed his firearms action-reaction experiment as a training
device to help his students better understand the concept of the
"reactionary gap." The reactionary gap is a human factors formula that
compares action vs. reaction. In humans, sudden action is usually faster
than a defensive response or reaction. The closer an assailant is to an
officer, the less time an officer has to defensively react to any aggressive
action the assailant makes.
Tueller has said in video interviews that he never designed nor presented
his firearms training drill as an organized, outlined, and implemented
research project involving the applied sciences of psychophysiology,
physics, and related human factors. No forensic testing, examination,
reconciliation of data, or scientific oversight of a research model was ever
conducted.
During the past 30 years since the 21-Foot Rule has become informal doctrine
within the law enforcement community, I have heard it misstated,
misrepresented, and bastardized by use-of-force, firearms, and police
practices experts from all sides. I actually reviewed an officer-involved
shooting case where an officer with a carbine shot and killed a suspect
armed with a knife from a distance of more than 150 feet and attempted to
use the "Tueller Drill" as his defense.
Instructors and experts also seem to have forgotten that the original
scenario of Lt. Tueller's drill involved an officer with a holstered sidearm
drawing and accurately firing his weapon. In the vast majority of
officer-involved shootings I have investigated or reviewed, the officers
already had their guns out of their holsters and were either at the "low
ready" position or directly aimed at the suspects who were either armed with
knives or furtively reaching into their waistbands.
So what are the real forensic facts that might assist officers with their
officer safety and deadly force determinations?
Actually, there are no forensically proven facts that I am aware of that
specifically verify or conclusively establish that a suspect armed with an
edged weapon will more likely than not be able to seriously injure or kill
an officer armed with a sidearm on all occasions and circumstances. The
truth is that the 21-Foot Rule should not be considered to be an absolute
rule at all because there are too many variables involved at this point to
call it a "rule." Let's discuss them.
The Variables
Psychophysiology-This is the study of how the brain influences and affects
physiological function. Science tells us that humans possess both a
forebrain and a midbrain. The forebrain is where cognitive processing and
decision-making take place. The midbrain plays a role in situational
awareness, sleep, arousal, alertness, and trained and subconscious memories.
When an officer experiences a threat, it takes on average .58 seconds to
experience the threat and determine if it is real. It then takes on average
.56 to 1.0 seconds to make a response decision. Humans have five possible
responses to threat: defend (fight), disengage (retreat), posture (yell,
point a finger, act aggressive), become hypervigilant (panic, confusion,
freezing, using force excessively), and submit (surrender).
When a human is threatened, the brain automatically infuses the body with
adrenalin (stimulant), endorphins (pain blockers), and dopamine (euphoric
pain blocker). The body uses these chemicals to help us survive an encounter
by making us faster, stronger, and more pain tolerant. However, these same
chemicals can also significantly diminish our performance under intense
stress by causing such problems as perceptional narrowing (tunnel vision),
loss of near vision, and auditory occlusion (reduced hearing) or exclusion
(loss of hearing). This ultimately negatively affects our chances of
surviving a violent encounter.
Under the intense stress normally associated with deadly force threat
scenarios and while under the influence of survival chemicals, the body's
basal metabolic rate, measured by heart rate, blood pressure, and
respiration, climbs significantly in milliseconds. This dynamic can cause
further psychophysiological impairments such as vasoconstriction, which can
impair weapon manipulation, cognitive processing, and stress memory recall
following an encounter.
Equipment and competency-Several factors affect an officer's survival
against an attacker. For instance, an officer or detective whose sidearm is
secured in a Level III holster will certainly have a slower draw-to-target
acquisition time than an officer drawing from a Level I holster. An
officer's experience and competency with his or her holster system and
combat shooting style are also critical human factors in that officer's
ability to draw, move off the line of attack, and direct accurate fire upon
an armed assailant.
Accuracy of fire at close distances-The average officer in static firearms
qualifications (non-timed, standing, and shooting without moving) can hit
the 9 and 10 rings far more often than not from the five-yard line. However,
research of actual OIS incidents has shown that officers can only accurately
hit their moving assailants 14% of the time in life-or-death situations from
distances of only two to 10 feet. On the other hand, assailants were able to
successfully engage and hit officers 68% of the time within those same
distances.
Perception lag-Once the average officer gets on target, it takes him or her
.56 seconds to make a decision to commence shooting. However, it then takes
that same officer .25 to .31/100ths of a second per trigger pull to fire. As
the deadly force scenario rapidly evolves, it takes that same officer on
average .5 to .6 seconds to realize that the threat has passed and to stop
shooting. This is because of a psychophysiological dynamic referred to as
"perception action-reaction lag time."
The reason why some suspects are found to have entry wounds in their sides
and backs when the officers who shot them say the suspects were facing them
when they fired is often the perception action-reaction lag time and the
manner in which information was processed by the officers' brains. This is
pretty sophisticated information for a criminal or civil jury to understand
and consider.
Fantasy or Forensic Fact
The fields of contemporary police practices and applied sciences are rapidly
changing. Applied science, by its nature, supports or rejects hypotheses and
theories based upon the reconciliation of scientific statements, facts, and
evidence. However, law enforcement is more inclined to be archaic and
married to non-forensic, speculative dogma that often goes unchallenged and
becomes widely accepted as fact.
It is my opinion that Lt. John Tueller did us all a tremendous service in at
least starting a discussion and educating us about action vs. reaction and
perception-reaction lag. This has certainly saved many lives within our
ranks. However, it is certainly time to move forward with a far more
scientific analysis that actually seeks to support or reject this
hypothesis.
Whether the "21-Foot Rule" is an applicable defense in an officer-involved
shooting actually depends upon the facts and evidence of each case. The
shooting of a knife-wielding suspect at less than 21 feet by an experienced,
competent, and well-equipped officer who has the tactical advantage of an
obstruction such as a police vehicle between herself and her attacker might
be inappropriate. But the shooting of a knife-wielding assailant at more
than 21 feet by an inexperienced officer, wearing a difficult holster
system, with no obstructions between herself and the attacker might be
justified.
As the 1989 U.S. Supreme Court ruling in Graham v. Connor (490 U.S. 386, 109
S.Ct) has eloquently stated, each high-risk encounter during a rapidly
evolving situation is unique. My sense is that future research may
underscore that legal principle with respect to the Tueller Drill.
Note: The author would like to thank forensic expert team members Homicide
Lt. Bob Prevot (Ret.), M.A., ballistic scientist/firearms expert Lance
Martini, M.S., firearms expert Larry Nichols, and NSW operational
psychologist and psychiatry professor Douglas Johnson, Ph.D., for reviewing
and contributing to this article.
Ron Martinelli, Ph.D., is a nationally renowned forensic criminologist
specializing in police death cases, use of force, human factors, and
psychophysiology. Dr. Martinelli is a retired law enforcement officer who
directs the nation's only multidisciplinary civilian Forensic Death
Investigation Team at Martinelli & Associates, Inc. He can be reached at
(951) 719-1450 and www.martinelliandassoc.com. His firm is presently engaged
in a major forensic scientific project reanalyzing the "21-Foot Rule." If
you are interested in volunteering for this important project, please
contact his office.
Related Video:
http://outfront.blogs.cnn.com/2014/08/22/how-are-cops-trained-for-deadly-for
References:
1.. The Tueller Drill, Video Interview with Lt. Dennis Tueller (Ret),
GunWebsites, 03-25-11
2.. How Close Is Too Close? (Article) Tueller, Dennis, SWAT Magazine,
03-1983
3.. Understanding & Leveraging the Psychophysiology of Emotional
Intensity, Sztajnkrycer, Matthew, M.D., Ph.D., Force Science Institute®,
Minnesota State University, Presentation at San Jose (CA) Police Department,
02-08-10
4.. Ibid.
5.. Processing Under Pressure: Stress, Memory and Decision Making in Law
Enforcement, Sharps, Matthew, Ph.D., © 2010, Loose Leaf Publishing,
Flushing, N.Y.
6.. Some fundamental of Human Performance: Applications to Police
Activities, Schmidt, Richard, Ph.D., Force Science Institute®, Minnesota
State University, Presentation at San Jose (CA) Police Department, 02-09-10
7.. Violent Encounters - A Study of Felonious Assaults on Our Nation's Law
Enforcement Officers, U.S. Department of Justice, Federal Bureau of
Investigations, Publication #0383, 2006
8.. Reaction Times in Lethal Force Encounters, The Tempe Study, (Article)
Lewinski, Bill, Ph.D., Hudson, Bill, Ph.D., The Police Magazine, Sept/Oct.,
2003, pp. 26 - 29
9.. The Psychology and Physiology of Deadly Conflict in War and in Peace,
Grossman, D.A., PPCT Research Publications, 2004
10.. Deadly Force Encounters: What Cops Need to Know to Mentally and
Physically Prepare for and Survive A Gunfight, Artwhol, A, Christensen, L,
Paladin Press, 1997
11.. Sharpening the Warrior's Edge: The Psychology & Science of Training,
PPCT Research Publications, 1995
12.. Motor Learning and Performance, Schmidt, R.A. and Wrisberg, C.A., 3rd
Edition, Human Kinetics Publishers, 2004
13.. Human Perception and Performance, (Article) Keetch, K.M., Schmidt,
R.A., & Young, D.E., Journal of Experimental Psychology, 2005, No. 31,
970-978
Tags:
Tueller Drill Knife Attacks Winning Edge